1. Field of the Invention
The present invention relates to a coordinate input device, and more particularly to a mouse whose movements on a flat surface are reflected by cursor movements on a visual display unit of a computer system.
2. Prior Art
Conventionally, a coordinate Input device such as a mouse is widely used for computer systems in business use for office work, engineering and the like, as well as for personal use in playing video games, drawing pictures or making documents containing tables. This device is useful for inputting two-dimensional coordinates, which designate a location to input a character on the screen or a location to start drawing a picture on the screen. Normally, the cursor displayed on the screen of the visual display unit is controlled in its location or coordinates by that device.
FIG. 2A is a sectional view showing a mechanical structure of the coordinate input device as conventionally known. This is a so-called mechanical mouse in which a rubber-coated ball 22 is rolling on a flat surface 31 so that the amounts of movement in X and Y directions are detected. Those movements are reflected by the two-dimensional movements of the cursor on the screen. This type of mouse is frequently used in the personal computer system.
In this device, a substrate 21 is fixedly located inside of a main body 20. Due to the provision of the main body 20, the substrate 21 and a ball-positioning member 24, the ball 22 is located at a certain position such that the ball 22 can rotate in any direction. The rotation of the ball 22 is converted into the location of the device on the flat surface 31.
FIG. 2B shows a construction of a rotation detector 26. Herein, a slit disk 34 is attached to an axis 32 such that the slit disk 34 can rotate about the axis 32. A plurality of slits are formed in the peripheral portion of the slit disk 34 at equal Intervals. A light-emitting element 36 is placed against a light-receiving element 38 with respect to the slit disk 34. The detection for the rotation of the ball 22 is activated when the operator moves the device in a certain direction on the flat surface 31 so that the ball 22 is correspondingly rotated. An edge portion of the slit disk 34 normally comes in contact with the ball 22; hence, the slit disk 34 should be rotated about the axis 32 by a certain amount of rotation in response to the rotation of the ball 22. The light emitted from the light-emitting element 36 passes through the slit to reach the light-receiving element 38. Since the slit disk 34 rotates responsive to the rotation of the ball 22, the light should intermittently reach the light-receiving element 38; in other words, the light-receiving element 38 receives a certain number of pulses of light in accordance with the rotation of the slit disk 34. The number of the pluses of light, received by the light-receiving element 38, is proportional to the amount of rotation of the ball 22 in a certain direction. The rotation detector 26, as shown in FIG. 2B, is provided for each of the X and Y directions; hence, it is possible to detect the amount of rotation of the ball 22 with respect to each of the X and Y directions. The pulses of light, received by the light-receiving element 38, are converted Into electric signals by a movement detecting means 28; and then, those electric signals are outputted from the device.
FIG. 3 is a sectional view showing a mechanical structure of another coordinate input device as conventionally known. This is a so-called opto-mechanical mouse having an optical detection means 46 by which the movements thereof are detected by reading a pattern written on a pad 40 so as to compute the amounts of movement in X and Y directions by a data conversion means 48.
Both of the devices described above are capable of obtaining coordinate information regarding the X and Y directions on the flat surface. In addition, those devices provide one or two buttons 29 and 49 as well. The buttons 29 and 49 are respectively connected with click detectors 30 and 50 which are fixedly located inside of the main body 20. The click detectors 30 and 50 detect ON/OFF states of the buttons 29 and 49 respectively, so that conversion means (not shown) converts the ON/OFF states detected into electric signals, which are outputted from the device. Further, the application program, executed by the computer, determines how the buttons function. For example, a task to select a specific function is assigned to one button, while a task to correct a specific item is assigned to another button.
The coordinate input devices conventionally known are useful in providing sufficient information regarding a two-dimensional coordinates system. Recently, however, videogame software or multimedia systems require more complicated movements for the cursor or graphic image on the screen. In some cases, three-dimensional movements are required. In that case, the conventional coordinate input device cannot sufficiently satisfy those needs.
When inputting a size or an intensity as a parameter regarding a certain object to be controlled on the screen, the conventional device inputs such parameter by detecting the time when the button is pushed or a duration in which the button is continuously pushed. Such indirect detection should be made by the conventional device because of the limited mechanism of the device. In that case, however, a change of the parameter on the screen which is caused by the conventional device does not precisely match the operator""s intention. In other words, to precisely match the change of the parameter with the operator""s intention, the operator should be skilled in manipulating the device. Therefore, the conventional device is not designed for people who are not skilled in manipulating the device. In addition, the conventional device cannot establish a good relationship between the screen image and the manipulation thereof.
It is an object of the present invention to provide a coordinate input device which is capable of inputting a variety of parameters with high performance.
The present invention provides improvements for coordinate Input devices such as the mechanical mouse, opto-mechanical mouse or the like which are used to control cursor movements in the visual display unit of the computer system. The coordinate input device according to the present invention comprises a position sensor and a pressure sensor. The position sensor detects a two-dimensional position of the device, which is moved on a flat surface or the like by a person, so as to produce two-dimensional coordinates. The pressure sensor detects pressing force applied to the device by the person. Hence, the two-dimensional coordinates and the pressing force detected are used as parameters which control a cursor or a graphic image displayed on the screen of the visual display unit.
The pressure sensor comprises an air-pressure sensor which detects a change of air pressure caused by the pressing force applied to the device. In addition, the pressure sensor can be replaced by a grip sensor which detects grip force applied to the device by the person.